The invention relates to high-temperature pipe supports, and in particular to high-temperature pipe supports for semiconductor apparatuses.
FIG. 1A is a partial cross section of a conventional chemical vapor deposition (CVD) apparatus. In FIG. 1A, the conventional CVD apparatus 10 comprises a seat 12, support ring 14, outer pipe 16, and inner pipe 18. The support ring 14 is disposed on the inner bore of the seat 12 near the bottom thereof. The inner pipe 18 and the outer pipe 16 are separately disposed on the seat 12 and support ring 14. The inner pipe 18 defines a sealed reaction chamber 182. During a CVD process, wafers are transferred into the reaction chamber 182 via a robot from the bottom entrance 184. The entrance 184 is closed and sealed, forming a vacuum in the reaction chamber 182 prior to CVD processes.
Due to the high operation temperature (above 700° C.) of CVD processes, the conventional inner pipe 18 and outer pipe 16 is quartz. The seat 12 and support ring 14 are stainless steel. The seat 12 is water-cooled from the outer bore and the sidewall adjacent to the gas outlet 122. After a number of CVD processes, silicide will coat the inner surfaces of the seat 12 and gas outlet 122. The coated silicide peels easily, however, producing particles P in the buffer space between the inner and outer pipes 16 and 18.
FIG. 1B is an enlarged view of area a in FIG. 1A. In order to easily position the inner pipe 18 during assembly, the conventional support ring 14 comprises a lead angle 144 around the inner upper edge such that particles P easily accumulate in the recess between the inner pipe 18 and the support ring 14. Particles P may be sucked into the reaction chamber 182 through the gap between the inner pipe 18 and the support ring 14 when the vacuum of the reaction chamber 182 is breaking and the entrance 184 is opened. Thus the silicide particles can be a principle reaction chamber contaminant source in a conventional CVD apparatus.